Treatment history: relationship to treatment outcomes.

It is important to understand whether the number of prior treatment episodes relate to treatment completion, discharge status, and 6-month outcomes. The data set contains information on 2,429 clients in treatment. A modified Addiction Severity Index was administered at the time of admission and at 6-months postdischarge. Additionally, length of stay and discharge status data were obtained. ANOVAs, MANOVAs, and chi(2) tests were used. Clients with the most prior treatment episodes had greater baseline substance use and psychosocial severity, and were more likely to be treated in residential settings. Nonetheless, treatment acceptance was greatest for these clients. Clients with no prior treatment reported the least acceptance. Treatment completion rates did not vary as a function of treatment experience. Clients achieved positive changes in multiple life domains regardless of treatment history. Nevertheless, at admission, discharge and follow-up, clients with >or= 2 treatments generally had greater problems than clients with fewer treatments.